// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_DISPATCHER_H_
#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_DISPATCHER_H_

#include <list>
#include <map>
#include <memory>
#include <string>
#include <vector>

#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/thread_checker.h"
#include "content/common/content_export.h"
#include "content/common/media/media_stream_options.h"
#include "content/public/renderer/render_frame_observer.h"
#include "content/renderer/media/media_stream_dispatcher_eventhandler.h"

namespace url {
class Origin;
}

namespace content {

// MediaStreamDispatcher is a delegate for the Media Stream API messages.
// MediaStreams are used by WebKit to open media devices such as Video Capture
// and Audio input devices.
// It's the complement of MediaStreamDispatcherHost (owned by
// RenderProcessHostImpl).
class CONTENT_EXPORT MediaStreamDispatcher
    : public RenderFrameObserver,
      public base::SupportsWeakPtr<MediaStreamDispatcher> {
public:
    explicit MediaStreamDispatcher(RenderFrame* render_frame);
    ~MediaStreamDispatcher() override;

    // Request a new media stream to be created.
    // This can be used either by WebKit or a plugin.
    // Note: The event_handler must be valid for as long as the stream exists.
    virtual void GenerateStream(
        int request_id,
        const base::WeakPtr<MediaStreamDispatcherEventHandler>& event_handler,
        const StreamControls& controls,
        const url::Origin& security_origin);

    // Cancel the request for a new media stream to be created.
    virtual void CancelGenerateStream(
        int request_id,
        const base::WeakPtr<MediaStreamDispatcherEventHandler>& event_handler);

    // Stop a started device that has been requested by calling GenerateStream.
    virtual void StopStreamDevice(const StreamDeviceInfo& device_info);

    // Request to open a device.
    void OpenDevice(
        int request_id,
        const base::WeakPtr<MediaStreamDispatcherEventHandler>& event_handler,
        const std::string& device_id,
        MediaStreamType type,
        const url::Origin& security_origin);

    // Cancel the request to open a device.
    virtual void CancelOpenDevice(
        int request_id,
        const base::WeakPtr<MediaStreamDispatcherEventHandler>& event_handler);

    // Close a started device. |label| is provided in OnDeviceOpened.
    void CloseDevice(const std::string& label);

    // Check if the label is a valid stream.
    virtual bool IsStream(const std::string& label);
    // Get the video session_id given a label. The label identifies a stream.
    // index is the index in the video_device_array of the stream.
    virtual int video_session_id(const std::string& label, int index);
    // Returns an audio session_id given a label and an index.
    virtual int audio_session_id(const std::string& label, int index);

protected:
    int GetNextIpcIdForTest() { return next_ipc_id_; }

private:
    FRIEND_TEST_ALL_PREFIXES(MediaStreamDispatcherTest, BasicVideoDevice);
    FRIEND_TEST_ALL_PREFIXES(MediaStreamDispatcherTest, TestFailure);
    FRIEND_TEST_ALL_PREFIXES(MediaStreamDispatcherTest, CancelGenerateStream);

    struct Request;

    // Private class for keeping track of opened devices and who have
    // opened it.
    struct Stream;

    // RenderFrameObserver override.
    void OnDestruct() override;
    bool Send(IPC::Message* message) override;
    bool OnMessageReceived(const IPC::Message& message) override;

    // Messages from the browser.
    void OnStreamGenerated(
        int request_id,
        const std::string& label,
        const StreamDeviceInfoArray& audio_array,
        const StreamDeviceInfoArray& video_array);
    void OnStreamGenerationFailed(
        int request_id,
        content::MediaStreamRequestResult result);
    void OnDeviceStopped(const std::string& label,
        const StreamDeviceInfo& device_info);
    void OnDeviceOpened(
        int request_id,
        const std::string& label,
        const StreamDeviceInfo& device_info);
    void OnDeviceOpenFailed(int request_id);

    // Used for DCHECKs so methods calls won't execute in the wrong thread.
    base::ThreadChecker thread_checker_;

    int next_ipc_id_;
    typedef std::map<std::string, Stream> LabelStreamMap;
    LabelStreamMap label_stream_map_;

    // List of calls made to the browser process that have not yet completed or
    // been canceled.
    typedef std::list<Request> RequestList;
    RequestList requests_;

    DISALLOW_COPY_AND_ASSIGN(MediaStreamDispatcher);
};

} // namespace content

#endif // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_DISPATCHER_H_
